1. Field of the Invention
The present invention relates to an electrodeless lamp apparatus using microwave, and particularly, to a filled material filled in a bulb of the electrodeless lamp apparatus.
2. Description of the Background Art
Generally, an electrodeless lamp system provides higher economical efficiency and idealistic natural light than any other conventional lamps.
The electrodeless lamp system is operated in following lighting mechanism. That is, microwave (high frequency) generated from a magnetron of a high frequency oscillator makes inert gas in a bulb into plasma, which is ionized status.
And above plasma status is maintained to make metal compound in the bulb emit light continuously, and thereby, high quantity of light can be provided without an electrode.
The above electrodeless lamp system has following properties.
Luminous flux corresponding to that of four metal halide lamps of 400 W can be generated by one electrodeless lamp system, energy consumption can be reduced by 20% or more, and a built-in stabilizer is used, and therefore, there is no need to use an additional stabilizer.
Also, the light is emitted by the plasma without a filament, and therefore, the lamp system can be used for a long time without lowering the flux.
Also, since continuous optical spectrum same as the natural white-light is realized by the electrodeless lamp system, it is able to function similarly to the sun light, and it is useful where the sun light is not streamed into or where color discrimination is made.
In addition, the electrodeless lamp system does not use fluorescent material to protect visual acuity, and is able to minimize radiation of infrared ray and ultraviolet ray to provide comfortable lighting environment.
FIG. 1 is a longitudinal cross-sectional view showing a conventional electrodeless lamp system.
As shown therein, the conventional electrodeless lamp system comprises: a magnetron 2 installed on inner upper end of a casing 1 for generating microwave; a bulb 5 located on upper part of the magnetron 2 and including luminescent material and buffer gas filled therein for generating light by making the filled fluorescent material into plasma by the microwave energy; a resonator 6 including the bulb 5 and passing the light generated from the bulb 5 while blocking the generated microwave; and a dielectric mirror 8 installed on lower part of the resonator 6 for transmitting the microwave generated from the magnetron 2 and reflecting the light.
The bulb 5 comprises: a light emitting portion 5a formed as a sphere using quartz, that is, light-transmitting material so that buffer gas, luminescent material and discharging catalyst material are filled therein, and a shaft portion 5b formed integrally on lower center portion of the light emitting portion 5a and coupled to a rotary shaft of a bulb motor (M1).
However, the light emitting portion 5a of the conventional bulb includes primary bulb fills emitting spectrum according to electron structure when it is excited to affect to emitting characteristics of the lamp, buffer gas contributing to initial discharge so that the primary bulb fills can be excited, and auxiliary bulb fill added in order to improve light property or to add a special function.
Sulfur (S) is used as the primary bulb fills filled in the light emitting portion 5a, and inert gas such as argon (Ar) (for example, Ne, Xe, Kr, etc.) is used as the buffer gas.
Also, halogenide of alkali metal (for example, Nal, KBr, etc.) and rare-earth halogenide (for example, Cal2, Bal2, etc.) is mainly used as the auxiliary bulb fill.
The conventional electrodeless lamp system as above is operated as follows.
First, when a driving signal is transferred to a controller, power source is supplied to the magnetron 2, and the magnetron 2 is oscillated by the power source to generate microwave having very high frequency.
Then, the microwave generated from the magnetron 2 is radiated into the resonator 6 to excite the buffer gas filled in the bulb 5, the sulfur, that is, the primary bulb fill becomes plasma continuously to generate the light having its own emission spectrum, and the light is reflected forward by a reflector and by the dielectric mirror 8 to enlighten the space.
However, according to the conventional electrodeless lamp system, luminosity factor is lowered and light efficiency is also lowered in case that the sulfur is used as the primary bulb fill, as shown in luminosity factor curved in FIG. 2.